Defect-induced Torques in Axially Strained Orthotropic Composite Belts and Plates

Abstract

Longitudinally reinforced flexible rubber plates and belts with vulcanized steel cords form a highly orthotropic composite. During fabrication, cords can buckle or move out-of-plane within the rubber matrix due to thermal and mechanical effects. Displaced cords within the cured composite will not carry full load when placed under axial tension. Belts with distorted cord planes mistrack due to variation of the physical centre-line of tension. Analysis of the mistracking problem requires measurement of variations in cord-plane flatness, followed by a moment analysis to calculate the torque imbalance due to misaligned cords. A model is described that uses cord alignment data to compute the torque imbalance relative to physical centre-lines. Using an inverse approach, analysis of a mistracking signature from a moving belt, band or plate can indicate the extent of built-in defects along the plates. The model has application to transform off-centre belt motion into an assessable defect level. The research has application to quantifying the limits of manufacturing quality in relation to existing Standards.